The son of two university professors, Stacey was killed in Helmand Province, Afghanistan in January 2012 at age 23 when he stepped on an improvised explosive device. On Friday at Camp Pendleton, he was posthumously awarded the Bronze Star for multiple acts of bravery during his third deployment to Afghanistan.

“He turned Marines into brothers and platoons into families,” said 1st Lt. Max Bernstein, who served with Stacey. “He volunteered to return to the fray time and time again, because he was a warrior in the true sense of the word.”

Stacey, a Seattle native, joined the Marine Corps in 2007 and went on five deployments in less than five years. He was a mortarman assigned to the 2nd Battalion, 4th Marine Regiment.

It was during his fifth deployment that Stacey, serving as squad leader, demonstrated remarkable guile and calm under fire to lead his men to safety on two occasions, according to his medal citation.

On Nov. 26, 2011, with his men facing enemy machine-gun fire from three locations, Stacey ran 200 meters over exposed ground through a barrage of enemy fire to lead his group into tactically advantageous terrain.

Then on Dec. 13, 2011, he led his men safely back to their patrol base after an hours-long firefight against superior enemy numbers, “unquestionably saving the lives of his Marines,” according to the citation.

“By his extraordinary guidance, zealous initiative and total dedication to duty, Sgt. Stacey reflected great credit upon himself and upheld the highest traditions of the Marine Corps and the United States Naval Service,” the document said.

Stacey showed a vast interest in military history from a young age, his parents remembered Friday. Bob Stacey, dean of the College of Arts and Sciences at the University of Washington, and Robin Stacey, a history professor at the same school, said their son insisted on becoming a Marine because it would be a challenging career and because he loved his country.

William Stacey played varsity baseball at Roosevelt High School in Washington and later attended a community college in Northern California. But after just six weeks there, he dropped out to enlist in the Corps.

“He loved teams,” Robin Stacey said. The Marine Corps “was the most important team he played for.”

Bob and Robin Stacey attended Friday’s ceremony with their 17-year-old daughter, Anna, and William’s former fiance, Kimmy Kirkwood. All four listened to stirring recollections about their loved one’s impact.

“He provided a lifetime of service in less than five years,” said Lt. Col. Robert Weiler, commanding officer of the 2nd Battalion, 4th Marine Regiment. “Every Marine in this battalion knows of Sgt. Stacey.”

Bernstein, the 1st lieutenant, described Stacey as the jock who would be picked first in football games and the nerd who devoured one book after another. He had “some serious swagger,” Bernstein said.

After the ceremony, several men presented Stacey’s family with a framed photo of his squad, complete with his medals.

“Courage is doing what the people who depend on you need you to do when they need you to do it, and that’s what he was doing in these combat actions,” Bob Stacey said. “Running 200 (meters) through enemy fire with no cover isn’t necessarily courage. It can be just craziness. It’s courage when that’s what the people who depend on you need you to do.”

Robin Stacey added: “I think it was really remarkable for me to see the Marines celebrate the life of my son. I hope Will was looking down to see how much he mattered to the people he worked with and the people he led.”